Would it be possible to write a code to burn a computer ?

[silvercats]

I mean physically harm it. damage the processor by overheating,memory etc??

Also "Does the programmer have to control memory manually in Assembly ?"

[<M/>]

You are creating a virus in that case?

[silvercats]

maybe

[deceptikon]

maybe

Discussion of virus implementation is prohibited on Daniweb. But yes, it's possible to physically harm hardware through software, if one is so inclined.

Also "Does the programmer have to control memory manually in Assembly ?"

Yes, unless you call into a library that manages memory for you.

[silvercats]

NO. Someone told me that it is a thing that can be done. but have never heard of a case like that. how can someone do that? my guess is ,only by using a bootable app using assembly?????

Yes, unless you call into a library that manages memory for you.

I thought ,in prtected mode ,OS does the memoery mangment while in the history , the programmer had to do it in flat model? (I guess) .

Manually manging memory means, assigning every integer to memory by typing its address by the programmer.

Let's say
int x=4 : if we have that, did they have to specifiy int x=4 at 0x000fe etc...? I mean enter the memory address by the prgrammer itself? in old modes? or do people still do this somehow

thanks

[silvercats]

it's possible to physically harm hardware through software, if one is so inclined.

why havn't we yet heard of a story about a virus that burned out the whole hardware ?is the OS protecting PC??

[deceptikon]

why havn't we yet heard of a story about a virus that burned out the whole hardware ?

Primarily because it's impractical for the same reason you don't hear about Linux or OSX viruses that often. The dependencies are fairly extreme, so the virus would only work on very specific hardware configurations.

is the OS protecting PC??

Defense mechanisms are in place, though not necessarily against malicious software. For example, if you've ever done any overclocking, you'll probably have encountered the situation where your processor overheats and the machine hard stops to avoid damage. That's a defense mechanism against overheating of the CPU.

Manually manging memory means, assigning every integer to memory by typing its address by the programmer.

That's not how it works, unless you're targeting a specific address like old DOS' real mode VGA locations. More often you're using the stack space provided by the OS and simply adjusting the stack pointer to reserve bytes for an object. Even in assembly language we don't manage memory in the way you've described unless our program is the operating system.

[silvercats]

cool thanks!

[silvercats]

Is there any other situation that needs memory to be handled in the way I described? when creating an OS ?

[silvercats]

That's not how it works, unless you're targeting a specific address like old DOS' real mode ""VGA locations""
what did you mean by that?

in old DOS real mode,did programmers have to manage memory (give addresses manually) like I described?

[mathematician]

It is possible, but you would really have to know what you were doing, and it is unlikely to happen by accident.

In assembly language the operating system is responsible for allocating memory, unless an operating system is what you are writing.

[salami1_1]

it is not possible what the H are you talking about.. this is -of course- hardware protected.. yes you can do some damage to for example the HD damaging MBR or VBR so it really doesn't work anymore (still can be fixed though just not by your average user)..

Perhaps theoretically when a CPU is overclocked and you have low-level access to memory functions and you can overwrite build-in protection from OS you can overheat it to do some real real damage.. however again why do you want to do this?

[mathematician]

@salami1 1: Have you ever heard of a motherboard virus? Some years ago there was a virus which programmed the chipset to erase the entire BIOS.

[silvercats]

They had to be booted before the OS right?

[salami1_1]

@mathematician
eeh yes did you read OP? He said physically damage.. erasing bios can be fixed and this is not physical damage.

Also I did a google search for your 'motherboard virus' and only thing that popped up was a virus that used the BIOS to infect MBR which I already mentioned.

And then again quoting yourself 'a few years ago'... the question is asked now and thus I assume this is about computers from now not from a few years ago as there is a huge difference.

[silvercats]

It is not a problem if it is a old PC or a new PC. Just wanted to know the theory.
If someone was able to erase the automatic shutdown part in BIOS and write a code to overuse the hardware probably it will work which is nowhere near easy

[mathematician]

@Salami1 1:
You might just as well say that setting fire to the motherboard wouldn't be physical damage, because the mother board could be replaced.

Also, the question was could the computer be physically damaged, and the answer is yes. What was done a few years ago could be done today. You might have thought that motherboard manufacturers would have been spurred into putting some elementary security precautions in place, but for the most part they weren't.

[salami1_1]

@math physical implies damage to property to a the machinery.. overwriting the bios code is a software issue (which then can be reprogrammed again).

Physical damage would be; putting the computer on fire, blowing a fuse, overloading CPU so it overheats and melts etc..

And for that motherboard manufacturers HAVE put securities in place

[mathematician]

"physical implies damage to property to a the machinery.. overwriting the bios code is a software issue (which then can be reprogrammed again)"

Not without physically replacing the bios it can't.
,
,
,
"And for that motherboard manufacturers HAVE put securities in place"

Less than a year ago I was in the market for a new motherboard, so I know otherwise.